Adaptive BTT terminal guidance law for hypervelocity vehicle

An adaptive proportional navigation guidance law is proposed for hypersonic vehicle terminal guidance. The vehicle could be guided to impact the target precisely in a specific direction with required circular error probable. Based on the analysis of longitudinal flight, a convergence strategy was designed to make the proportional navigation guidance works earlier. The strategy allowed more time for the vehicle to meet the heading constraints at the impact. The precision of impact was affected by guidance parameters directly. However, vehicle would not conduct guidance commands ideally because of dynamic constraints. A close-loop nonlinear adaptive law was introduced to update guidance parameters online to improve the impact precision. Simulation results demonstrate the affectivity and accuracy of the proposed method.